Disclosed is apparatus for transferring drill rods between a rod rack and a drill rig in a position for respectively being coupled to and removed from a drill string.
Generally drill rods longer than 3 meters are too heavy to be conveniently manually handled for transferring a rod between a rod stacking area and a position for being coupled to a drill string. Generally in prior art rod handlers, the drill rods must be stored in special arrays (special stacking arrangements) with the stack divided into rows and with the rods separated by at least a predetermined dimension, to be gripped by the rod gripping assembly of a rod handler. When different diameter rods are to be used, adjustments in the stacking array structure has to be made. Further, prior art rod handlers generally require two spaced rod gripping devices to ensure the rod remaining rigid when clamping gripped. Also rotation of a drill rod by a powered swivel action of the gripping devices is required because, other than for rotary turrets or turntables storing rods, usually the bore hole axis is not aligned with the axes of the rods in the rod rack (stacked storage position). To transfer a drill rod from a stacking area to a position in a drilling machine requires a drill rod to be moved in four ways: 1) x axis; 2) Y axis; 3) Z axis; and 4) rotation. International Publication Number WO87/04754 to Jonsson discloses rod handling apparatus having a boom mounted for horizontal movement by a housing that is, in turn, mounted for vertical movement. The boom depending mounts a rod having a rod gripping assembly and control mechanism mounted thereon. This requires the operator to be closesly adjacent to a gripped drill rod. Berry, U.S. Pat. No. 4,715,761, discloses rod handling apparatus for moving a drill rod between a storage position and a bore hole aligned position. The apparatus includes a base that is rotatable about a vertical axis by a motor. The base in turn mounts parallel tracks which mount a carriage for movement by a hydraulic ram. A multisection telescopic boom is carried by the carriage and is pivotable relative to the carriage about a horizontal axis by a piston cylinder. One end of the boom mounts a jaw device for gripping a rod.
U.S. Pat. No. 4,345,864 to Smith, Jr. et al. discloses rod handling apparatus for moving a pipe that includes a turret dependingly mounting a vertical leg. Linkage mechanism is mounted by the vertical leg for translating rod gripping mechanism between two horizontally spaced positions. The rod gripping mechanism includes a pair of power operated jaws mounted for pivotal movement about a vertical axis, the rack having a fingerboard for retaining rows of pipes in spaced relationship.
U.S. Pat. No. 4,269,554 to Jackson includes a table that appears to be reciprocally moved toward and away from the inside of a derrick. The table mounts a transfer arm frame for pivotal movement about a vertical axis while the arm frame mounts a power operated gripping device for gripping rods supported by a fingerboard in parallel relationship to the bore hole axis.
In order to make improvements in rod handling mechanism and overcome limitations encountered by apparatus of the general nature of the above mentioned prior art, this invention has been made.